iwlagn: track beacon interval sent to device

Sometimes, when mac80211 changes the beacon
interval or when it isn't yet set in mac80211
before association, the uCode will sysassert
because we send it confusing RXON timing vs.
PAN parameters. To fix this, track the last
beacon interval sent to the device and use
that in PAN parameter calculations.

This fixes a bug during P2P group formation
as a client (and possibly association to a
regular AP) while connected to another AP.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

drivers/net/wireless/iwlwifi/iwl-agn-rxon.c

@@ -342,22 +342,21 @@ int iwlagn_set_pan_params(struct iwl_priv *priv)
 		slot1 = priv->hw_roc_duration;
 		slot0 = IWL_MIN_SLOT_TIME;
 	} else if (ctx_bss->vif && ctx_pan->vif) {
-		int bcnint = ctx_pan->vif->bss_conf.beacon_int;
+		int bcnint = ctx_pan->beacon_int;
 		int dtim = ctx_pan->vif->bss_conf.dtim_period ?: 1;
 
 		/* should be set, but seems unused?? */
 		cmd.flags |= cpu_to_le16(IWL_WIPAN_PARAMS_FLG_SLOTTED_MODE);
 
 		if (ctx_pan->vif->type == NL80211_IFTYPE_AP &&
 		    bcnint &&
-		    bcnint != ctx_bss->vif->bss_conf.beacon_int) {
+		    bcnint != ctx_bss->beacon_int) {
 			IWL_ERR(priv,
 				"beacon intervals don't match (%d, %d)\n",
-				ctx_bss->vif->bss_conf.beacon_int,
-				ctx_pan->vif->bss_conf.beacon_int);
+				ctx_bss->beacon_int, ctx_pan->beacon_int);
 		} else
 			bcnint = max_t(int, bcnint,
-				       ctx_bss->vif->bss_conf.beacon_int);
+				       ctx_bss->beacon_int);
 		if (!bcnint)
 			bcnint = DEFAULT_BEACON_INTERVAL;
 		slot0 = bcnint / 2;
@@ -376,7 +375,7 @@ int iwlagn_set_pan_params(struct iwl_priv *priv)
 	} else if (ctx_pan->vif) {
 		slot0 = 0;
 		slot1 = max_t(int, 1, ctx_pan->vif->bss_conf.dtim_period) *
-					ctx_pan->vif->bss_conf.beacon_int;
+					ctx_pan->beacon_int;
 		slot1 = max_t(int, DEFAULT_BEACON_INTERVAL, slot1);
 
 		if (test_bit(STATUS_SCAN_HW, &priv->status)) {

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -363,6 +363,8 @@ int iwl_send_rxon_timing(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
 		ctx->timing.beacon_interval = cpu_to_le16(beacon_int);
 	}
 
+	ctx->beacon_int = beacon_int;
+
 	tsf = priv->timestamp; /* tsf is modifed by do_div: copy it */
 	interval_tm = beacon_int * TIME_UNIT;
 	rem = do_div(tsf, interval_tm);

drivers/net/wireless/iwlwifi/iwl-dev.h

@@ -1152,6 +1152,8 @@ struct iwl_rxon_context {
 
 	__le32 station_flags;
 
+	int beacon_int;
+
 	struct {
 		bool non_gf_sta_present;
 		u8 protection;